6. Brave New Worlds

By Jeffrey KlugerMonday, Nov. 03, 2008

NASA / Getty

It's getting crowded out there. Scientists have always been certain that the universe was aswarm with planets orbiting stars other than our own little sun, but it wasn't until 1995 that they started to find these so-called exoplanets. Most of them were huge worlds lying too close to their parent stars to harbor life. In June, Swiss astronomer Michel Mayor found 45 much smaller worlds, one only 4.2 times as big as Earth. All of them inscribe small, scorchingly hot orbits too, but Mayor's instruments  which detect planets by the gravitational wobbles they cause their suns  should be sensitive enough to find ones with larger orbits that place them out in cooler, arguably habitable regions. In November, two teams of astronomers from the U.S. and Canada got four exoplanets to sit still for their photographs, producing the first ever images of alien worlds in visible and ultraviolet light.